Why is there a "Human" tag, and only some "Humans" have it?

What is this tag even for in the Star Wars universe?

STHan is a human, but Han Solo isn't? Biggs isn't? Luke is, Leia isn't? Anakin is but QGJ isn't? The strange list goes on but you get my point.

Just curious if it was ever going to be used for anything...because if so it need to be cleaned up quite a bit.